"Operation could destabilize the runtime" error when running Evaluate() or HasErrors()

Hi! After having looked around a bit for a calculation parser, I found NCalc. Today I finally reached the point where I though I could start using it. For a start I wanted NCalc to validate the syntax of some expressions. But as soon as I run HasErrors()
or Evaluate(), I get a "Operation could destabilize the runtime" error which makes it impossible for me to test NCalc locally. On my local development machine I'm running the app from IIS 7 (or is it 7.5?) on Windows Server 2008R2. If I upload the
app to my web host it works just fine which is opposite to what these kinds of problems usually are. Is this anything you've seen before and know how to solve?